The present invention relates to an apparatus which includes a speaker and a microphone, such as a telephone, intercom, two-way radio and the like, and more particularly, to an apparatus which includes a speaker and a microphone which provides acoustical and mechanical isolation between the speaker and a microphone to provide improved audio performance as well as allow for streamlined manufacturing of the apparatus and thus reduced costs.
Various apparatus are known which include speakers and microphones, carried by a common housing. Speaker phones, intercoms, two-way radios and the like are examples of such apparatus. There are several known disadvantages of such apparatus. First, such apparatus are known to have undesirable audio performance resulting from non-linear mechanical coupling between the speaker and the microphone. More particularly, in many known apparatus, the speaker energy is known to cause non-linear vibration of the microphone support structure which carries the microphone which, in turn, is coupled to the microphone. Second, the loudspeaker energy is known to cause vibration of various parts within the apparatus, which can produce non-linear vibrational noise, known to be acoustically coupled to the microphone. Third, the second waves from behind the speaker are known to cancel sound waves in front of the speaker, thus degrading audio performance.
Another known problem with such existing apparatus is the complexity of assembly. In particular, known apparatus for housing speakers and microphones are known to include a relatively large number of parts and require a relatively large number of steps for assembly. As such, such known apparatus are relatively expensive to manufacture. Thus, there is a need to provide an apparatus which causes a microphone and speaker which provides increased audio performance as well as facilitates manufacturing thus reducing the cost of the apparatus.
In accordance with the present invention, an apparatus is formed with a sealed chamber behind the speaker which provides improved isolation between the speaker and microphone to prevent sound waves behind the speaker from cancelling sound waves in front of the speaker. In addition, the speaker is mechanically isolated from the apparatus housing in order to improve performance of the system. A pliant material, such as a damping material with a relatively linear compression characteristic, such as a thermal plastic elastomer, may be used to isolate the speaker from the apparatus housings as well as providing a relatively air tight chamber behind the speaker.